This project seeks, by studying various visual functions under scotopic and photopic conditions, to relate the visual deficits of strabismic and anisometropic amblyopias to the Duplicity Theory of Vision. Eccentricity of fixation is measured with an on-campus developed Maxwell's spot method with a precision of 0.1 degrees. Offset (Vernier) acuity is measured at different points in the visual field and at different luminances and under specific illuminants. The course of dark-adaptation of normal, amblyopic and dominant eyes are compared. The Stiles-Crawford Effect 1 of normal, amblyopic and dominant eyes are compared and a new instrument is being developed to precisely measure the location in the pupil, of the peak of the function. A study of eccentricity and stereopsis is under development. The results are expected to bear upon several theories of amblyopia, particularly the Wald-Burian pattern - vision dissociation hypothesis of amblyopia. The results of the project to date show that dominant eyes are not normal eyes.